in Terms of the Mechanical Equivalent of Heat. 



Baudin 7320. 





Temperature 





Temperature 



Reading. 



on absolute 



Beading. 



on absolute 





scale from 0° 0. 





scale from 0° C. 



o 



o 



o 



o 







0-122 



23 



23-108 



5 



5-092 



24 



24-122 



10 



10-110 



25 



25-137 



]5 



15-090 



26 



26-152 



16 



16093 



27 



27-166 



17 



17094 



28 



28-179 



18 



J 8091 



29 



29-192 



19 



19-086 



30 



30205 



20 



20-081 



31 



31-217 



21 



21-085 



32 



32-230 



22 



22095 







The table for 6165 is condensed from Professor Rowland's 

 paper* on the mechanical equivalent. Change in the zero 

 point has no effect on the differences of temperature used, but 

 the zero points were determined occasionally in order to get 

 the mean absolute temperature. 



The correction for radiation was made in the following 

 manner : — The groups of thermometer-readings taken after 

 breaking the circuit were reduced to mean readings at mean 

 times. Any two of these mean readings gave the radiation 

 for the intervening time. If t' and t" are the temperatures 

 at the beginning and end of an interval of T minutes, and r 

 is the mean temperature of the jacket during the interval, then 



where c is the coefficient of radiation. In the calculation of 

 c, stem-corrections were applied and a correction made for the 

 heat generated by the stirrer. Hence in the main experiment 

 the temperature-correction for an interval T' is 



A = cT'[^/ + / / )--t'] + K, 



where s f and s" are the observed temperatures corrected for 

 stem-error, r f is the mean temperature of the jacket, and K is 

 the stirrer- correction. The sum of the corrections A from the 

 beginning of the experiment added to the stem-corrected ob- 

 served temperature at any point, gives the temperature which 

 would have been reached in the absence of radiation. The 

 difference between any two of these theoretical temperatures 

 multiplied by the heat -capacity, gives the heat generated in 

 the interval. 



* Proceedings of American Academy of Arts and Sciences, 1880. 



